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Full text of "Treatise On Applied Analytical Chemistry(Vol-1)"

ALMOND OIL

ALMOND   OIL

This is obtained from the seeds of Amygdalus communis or ordinary
almonds, the sweet and bitter varieties giving oils very similar in all their
properties. Almond oil is yellow or golden-yellow and about 16 grams of
it dissolve in 1000 c.c. of absolute alcohol.

With Heydenreich's, Hauchecorne's and Brulle's reagents L remains
pale yellow or becomes somewhat paler. The characters of the oil are
given in Table XLIV and are determined by the methods already described.

Detection of Adulterations.—Almond oil may be adulterated with
various seed oils (arachis, colza, cottonseed, walnut, sesame, etc.), but
especially with peach-kernel, apricot-kernel and plum-kernel oils. To
detect such admixtures, the various characters must be determined (especi-
ally solidifying points of the oil and of the fatty acids, saponification and
iodine numbers, Maumene number) and certain colour tests made (see
below, 2).

The different extraneous oils may be detected as follows:

1.  ARACHIS, SESAME, COTTONSEED, COLZA, ETC.   The first is detected
by the arachidic and lignoceric acids, the second by the furfural reaction,
the third by the Halphen reaction, and colza oil by tests on the fatty acids
(see the respective oils).    The presence of other seed oils in general (exclud-
ing those dealt with in 2) may be recognised by the colour reactions of
Heydenreich, Hauchecorne, Brulle and Bellier (see General Methods, 23),
to which almond oil does not sensibly respond.

2.  PEACH-KERNEL, APRICOT-KERNEL AND PLUM-KERNEL OILS.   These
oils are commonly used as adulterants or substitutes for almond oil.   They
do not alter the characters of almond oil appreciably, excepting that apricot-
kernel oil somewhat increases the Maumene number (50-51 for almond oil
and 60-70° for apricot-kernel oil).   The two following reactions serve for
their detection.

Bieber's reaction. Equal volumes of pure sulphuric acid of 66
concentrated nitric acid (D 1-42) and water are mixed, one vol. of
mixture being then shaken with 5 vols. of the oil in the cold. Pure almon^j
oil forms a yellowish emulsion which becomes reddish only after some timJLSs
Apricot-, peach- and plum-kernel oils form emulsions of a transient
colour, which soon changes to deep orange and then to brown.

Reaction with nitric acid.    I c.c. of fuming nitric acid, I c.c. of
and 2 c.c. of the oil are shaken vigorously at a temperature of about TO T
pure almond oil yields a whitish emulsion which, in two or at
hours, sets to a solid mass of compact white granules with a little co
less, supernatant liquid.   In presence of apricot- or peach-kernel oi
emulsion becomes coloured, almost immediately, more or less re
If the solid mass and the liquid turn brown, the presence of other extrajre@*is
oils (colza) is demonstrated.

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For medicinal uses, pharmacopoeias prescribe the oil obtained by
from sweet almonds.

The Official Italian Pharmacopeia requires sweet almond oil to

tances up to 1-5%, and moisture and various other impurities